1. Field of the Invention
This invention relates to a multi-purpose clamping apparatus for pressing the confronting edges or ends of two boards or other components during a gluing process.
2. Description of the Prior Art
In the practice of woodwork crafting the occasion often arises where boards or other components of wood or composites or other man-made materials are to be joined together along proximate edges or ends to provide a composite frame, border or panel to be integrated into a piece of furniture or molding. For narrow slats and the like, conventional clamps and vises, having a bite sufficient to span the width of the boards or items being joined, are satisfactory to engage the opposite sides of such boards and press them firmly together at the edges to be joined. However, difficulty is encountered when the boards to be joined are collectively wider than the bite of a conventional vise. A challenge is also presented when the boards are to be joined endwise thus requiring gripping of the boards for application of compressive forces in the longitudinal direction. The challenges encountered are compounded when the boards to be joined are to project at various angles, such as 90.degree. to one another. In practice, it is desirable to orient the components in edgewise contacting relation ("dry joint") to secure the relative positioning so as to visually check the fit and then, if satisfactory, separate such components to space the components apart for access to the mating edges for application of glue while monitoring the relative component orientation for repeating the mating fit with the glued edges. Numerous differed devices have been proposed in effort to solve the problems encountered in joining wide boards together laterally, lay boards together endwise, and other boards together at various uncommon angles.
One such mechanical device for clamping together of the confronting edges of boards during a gluing process incorporates a vise-like bar-clamp having two jaws at opposite ends of a bar that draw together boards placed in-between as the jaws are drawn together in a screw-like action. These vise-like clamping devices must more or less vary in size in direct relation to the composite span of the boards to be joined. Where large boards, such as plywood or particle board, or odd shapes, such as round stock, are used, the task of aligning the boards and clamping the boards in-between bar clamps can be burdensome indeed.
Another clamping device proposed for joining wide boards edgewise includes a screw to draw two barrel nuts together that are inserted within pilot holes drilled into the boards. The joint is secured tightly by adjusting the screw between the two barrel nuts. While such a clamping device is not size dependent in relation to the scale of the boards, the device does require that pilot holes be drilled into the surface of the boards in order to secure barrel nuts. Drilling of these holes requires care and skill to avoid unwanted damage such as accidental drilling through to the opposite face and in any event leaves the unsightly holes visible in the finished product themselves. Moreover such devices are not adaptable for practical use in joining oddly configured components such as round stock or cylindrically shaped molding.
Other efforts to solve the problem led to the development of a clamp having an elongated rail carrying a push plate driven therealong by a drive screw to push one board against the edge of another held in place on such rail by a grip jaw, U.S. Pat. No. 3,603,580. One such clamp device is marketed by Universal Clamp Corp. of Van Nuys, Calif. Such devices, while satisfactory for some applications, suffer the shortcoming that there is no provision for making a dry joint contact of the board edges to establish relative orientation of the boards and then holding them in such fixed relative orientation while they are separated for application of glue and subsequent compressed contact with one another.
Finally, for smaller pieces, an adjustable corner and splicing clamp has been employed consisting of a pair of vise-like clamps adjustably mounted on a protractor for clamping miter or butt joints at any selected angle as required. In a device of this type, the two vises are rotated into position along the protractor and the boards may be secured at their widths by the vises. While such devices work well for picture frames and the splicing of molding and trim, the vise clamps prove inadequate for securing larger boards together.
Wood workers have from time to time been forced to rely on trial and error techniques which often include extensive shaving or sanding of the confronting edges prior to the application of glue to the confronting edges.
None of the clamping devices or techniques of the prior art offer a practical device allowing for alignment of the boards to be glued to establish the desired orientation and alignment and then for separation to expose the confronting edges for application of glue or other bonding material while monitoring such established orientation and alignment for pressing of such boards back together without requiring that the boards be realigned.
In my parent patent application Ser. No. 08,123,874, filed Sep. 20, 1993, and now U.S. Pat. No. 5,401,354, I disclose a clamping apparatus characterized by a pair of base plates formed with upwardly facing support surfaces for securing a pair of respective components thereon during the process of gluing their confronting edges together wherein each base plate includes respective clamps to maintain the respective boards fixed against the base plates. Included between the two base plates is a rail that couples the first and second base plates together and permits movement of the second base plate therealong permitting the two base plates, with the components affixed therein, to be separated for access of glue to the edges, and then to be pressed together without disturbing alignment of such components. A trigger shaped press, mounted on the second base plate, when actuated, incrementally draws the second base plate along the rail towards the first base plate firmly pressing the confronting edges of the two boards clamped thereon together. Such a device, while acceptable for its intended purposes and having substantial commercial utility, has a multiplicity of odd shaped parts thus making the device costly to manufacture. In addition, the latching, indexing and biasing functions are carried out by complex sub-assemblies lessening the reliability and durability of the device.
Consequently, there exists a need for a clamping apparatus having sub-assemblies which are simpler and easier to build so as to comprise a device which is more reliable and durable, while being inexpensive to manufacture.